TW202411173A - Coated glass substrate and manufacturing method thereof - Google Patents

Abstract

The present invention provides a film-coated glass substrate that can achieve both anti-glare and scratch resistance to a high degree. The film-coated glass substrate 1 of the present invention comprises: a glass substrate 2; and an anti-glare film 3, which is disposed on the main surface 2a of the glass substrate 2 and has silicon oxide as a main component; and the arithmetic mean height Sa of the surface 3a of the anti-glare film 3 is greater than 0.3 μm, and in the pencil hardness test of JIS K5600-5-4:1999, when the surface 3a of the anti-glare film 3 is observed at a magnification of 100 times using a metal microscope to determine whether the surface 3a of the anti-glare film 3 is damaged, the pencil hardness is greater than 7H.

Description

Film-coated glass substrate and manufacturing method thereof

The present invention relates to a coated glass substrate with an anti-glare film and a manufacturing method of the coated glass substrate.

Previously, in displays such as mobile phones, tablet terminals, televisions, or digital signage, there was a situation where the visibility was reduced due to reflected images reflected on the display surface due to indoor lighting (fluorescent lights, etc.) or external light such as sunlight. As a treatment to suppress the reflection caused by such external light, anti-glare treatment and anti-reflection treatment are known.

The following patent document 1 discloses a cover glass, which includes: a glass plate, and an anti-glare layer disposed on the glass plate. In patent document 1, an anti-glare layer is formed on the glass plate by applying an inorganic coating by a spraying method, thereby imparting an anti-glare effect to the cover glass. As the main component of the above-mentioned inorganic coating, a silicon dioxide precursor, an aluminum oxide precursor, a zirconium oxide precursor, a titanium oxide precursor, etc. are used. [Prior art document] [Patent document]

[Patent Document 1] International Publication No. 2020/218056

[The problem the invention is trying to solve]

In recent years, a higher anti-glare property is required for a coated glass substrate such as that of Patent Document 1. At this time, in order to improve the anti-glare property, a method of increasing the thickness of the anti-glare film is considered. However, if the thickness of the anti-glare film is increased, the scratch resistance is reduced. As a result, there is a problem that a large amount of damage occurs to the anti-glare film due to long-term use.

The purpose of the present invention is to provide a film-coated glass substrate that can achieve both anti-glare and scratch resistance to a high degree and a method for manufacturing the film-coated glass substrate. [Technical means for solving the problem]

Various aspects of a coated glass substrate and a method for manufacturing the coated glass substrate for solving the above-mentioned problems are described.

The feature of the coated glass substrate of the embodiment 1 of the present invention is that it comprises: a glass substrate; and an anti-glare film, which is arranged on the main surface of the above-mentioned glass substrate and has silicon oxide as a main component; and the arithmetic mean height Sa of the surface of the above-mentioned anti-glare film is greater than 0.3 μm, and in the pencil hardness test of JIS K5600-5-4:1999, when the surface of the above-mentioned anti-glare film is observed at a magnification of 100 times using a metal microscope to determine whether the surface of the above-mentioned anti-glare film is damaged, its pencil hardness is greater than 7H.

Regarding the coated glass substrate of aspect 2, it is preferred that in aspect 1, the coated glass substrate has a haze of 30% or more as measured according to JIS K7136:2000.

Regarding the film-coated glass substrate of aspect 3, it is preferred that in aspect 1 or 2, the strain point of the glass substrate is 550° C. or higher.

Regarding the coated glass substrate of Aspect 4, it is preferred that in any one of Aspects 1 to 3, the ratio of the root mean square height Sq of the surface of the anti-glare film to the minimum autocorrelation length Sal (Sq/Sal) is greater than 0.05.

The manufacturing method of the coated glass substrate of aspect 5 of the present invention is characterized in that it includes: a step of forming a coating film with projections and depressions on a glass substrate by spraying a coating liquid containing a silicon dioxide precursor; and a step of forming an anti-glare film by firing the coating film at a temperature above 500°C; and the anti-glare film is formed in such a way that the arithmetic mean height Sa of the surface of the anti-glare film becomes above 0.3 μm.

Regarding the method for manufacturing a film-coated glass substrate of Aspect 6, it is preferred that in Aspect 5, when the coating film is fired, the coating film is fired at a temperature below the strain point of the glass substrate.

Regarding the method for manufacturing a film-coated glass substrate of Aspect 7, it is preferred that in Aspect 5 or 6, the strain point of the glass substrate is above 550°C.

Regarding the method for manufacturing a coated glass substrate of Aspect 8, it is preferred that in any of Aspects 5 to 7, the silicon dioxide precursor comprises: at least one of an N-functional silane oxide (N=2, 3, 4) and a hydrolysis condensate of the N-functional silane oxide. [Effect of the invention]

According to the present invention, a film-coated glass substrate having both anti-glare and scratch resistance to a high degree and a method for manufacturing the film-coated glass substrate can be provided.

The following describes a preferred embodiment. However, the following embodiment is only for illustration, and the present invention is not limited to the following embodiment.

[First embodiment] (Film-coated glass substrate) FIG. 1 is a schematic cross-sectional view of a film-coated glass substrate of the first embodiment of the present invention. As shown in FIG. 1 , the film-coated glass substrate 1 includes: a glass substrate 2 and an anti-glare film 3. The anti-glare film 3 is provided on the glass substrate 2.

In the present embodiment, the glass substrate 2 has a substantially rectangular plate shape. However, the glass substrate 2 may also have a substantially circular plate shape, and its shape is not particularly limited.

The glass substrate 2 is preferably a glass substrate that transmits at least a portion of light in the wavelength range of 450 nm to 700 nm. The glass substrate 2 is preferably a transparent glass substrate. In this specification, "transparent" means that the transmittance in the visible light wavelength range of 450 nm to 700 nm is 70% or more.

The strain point of the glass substrate 2 is not particularly limited, but is preferably 500°C or higher, more preferably 550°C or higher, further preferably 560°C or higher, further preferably 570°C or higher, particularly preferably 580°C or higher, further particularly preferably 590°C or higher, further particularly preferably 600°C or higher, further particularly preferably 610°C or higher, most preferably 620°C or higher, particularly preferably 630°C or higher, further particularly preferably 640°C or higher, further particularly preferably 650°C or higher, further particularly preferably 660°C or higher, further preferably 670°C or higher, further particularly preferably 680°C or higher. In this case, even when the glass substrate 2 is fired at a high temperature in the following manufacturing step, the strain of the glass substrate 2 is less likely to remain, and the deformation of the film-coated glass substrate 1 can be further suppressed. Therefore, when the coated glass substrate 1 is used in a display, etc., the visibility can be further improved. In addition, the upper limit of the strain point of the glass substrate 2 is not particularly limited, and can be set to 1000°C, for example.

The strain point of the glass substrate 2 can be measured according to ASTM C336. In addition, the strain point of the glass substrate 2 can be increased by a known method (e.g., Japanese Patent Publication No. 2002-308643, Japanese Patent Publication No. 2012-041217, Japanese Patent Publication No. 2002-029776, Japanese Patent Publication No. 2006-252828, Japanese Patent Publication No. 2022-008627, Japanese Patent Publication No. 08-295530, etc.). In particular, the strain point of alkali-free glass that does not substantially contain (e.g., less than 0.1%) alkali metal oxides is likely to be high, and it is also preferred from the viewpoint of further improving scratch resistance and chemical resistance.

The glass used for the glass substrate 2 is not particularly limited, and for example, borosilicate glass, aluminosilicate glass, quartz glass, crystallized glass, etc. can be used. Furthermore, since there is a risk of poor chemical strengthening when sintering at a high temperature in the following manufacturing steps, the glass used for the glass substrate 2 is preferably not a chemically strengthened glass.

The glass used for the glass substrate 2 may contain, for example, SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , alkali earth metal oxides, alkali metal oxides, SnO ₂ , and the like.

SiO ₂ is a component of the network former (network forming oxide) that forms the glass. The content of SiO ₂ can be set to 50% to 75% by mass, for example. When the content of SiO ₂ is above the lower limit, the strain point of the glass can be further increased. On the other hand, when the content of SiO ₂ is below the upper limit, the high temperature viscosity can be reduced, and the melting property of the glass can be further improved.

The content of Al ₂ O ₃ can be set to 8% to 25% by mass percentage, for example. When the content of Al ₂ O ₃ is above the lower limit, the strain point of the glass can be further increased. In addition, the glass can be less likely to undergo phase separation. On the other hand, when the content of Al ₂ O ₃ is below the upper limit, the liquidus temperature of the glass is less likely to increase.

B ₂ O ₃ is a component that reduces the high temperature viscosity of glass and improves its solubility. The content of B ₂ O ₃ can be set to 0.01% to 15% by mass, for example. When the content of B ₂ O ₃ is above the lower limit, the solubility of the glass can be further improved. On the other hand, when the content of B ₂ O ₃ is below the upper limit, the strain point of the glass can be further increased.

Alkali earth metal oxides are components that reduce the high temperature viscosity of glass and improve its solubility. Examples of alkali earth metal oxides include MgO, CaO, SrO, BaO, etc. These can be used alone or in combination. The content of alkali earth metal oxides (the total amount when multiple types are included) is, for example, 0.1% to 20%, 1% to 20%, 5% to 20%, and 10% to 20% in terms of mass percentage. When the content of alkali earth metal oxides is above the above lower limit, the solubility of the glass can be further improved. On the other hand, when the content of alkali earth metal oxides is below the above upper limit, the strain point of the glass can be further increased. In addition, the component balance of the glass composition can be less likely to be broken, and devitrified crystals can be less likely to precipitate.

Alkali metal oxides are components that improve the solubility of glass. Examples of alkali metal oxides include Li ₂ O, Na ₂ O, and K ₂ O. These may be used alone or in combination. The content of the alkali metal oxide (the total amount when multiple types are included) is preferably 0.01% or more, more preferably 0.02% or more, further preferably 0.05% or more, preferably 24% or less, more preferably 20% or less, further preferably 10% or less, further more preferably 5% or less, particularly preferably 3% or less, further particularly preferably 1% or less, most preferably 0.5% or less, particularly preferably 0.3% or less, and further particularly preferably 0.1% or less. When the content of the alkali metal oxide is above the above lower limit, the solubility of the glass can be further improved. On the other hand, when the content of the alkali metal oxide is below the above upper limit, the strain point of the glass can be further increased.

SnO ₂ is a component that has a good clarification effect in a high temperature range and increases the strain point of glass. The content of SnO ₂ can be set to 0% to 1% by mass percentage, for example. When the content of SnO ₂ is above the lower limit, the strain point of the glass can be further increased. On the other hand, when the content of SnO ₂ is below the upper limit, the glass is less likely to lose clarity.

In addition to _{the above-mentioned components, the glass used in the glass substrate 2 may also contain other components such as ZnO, P2O5, TiO2, Y2O3 , Nb2O5 , La2O3 , etc. Other components} may be used alone or in combination. Furthermore, other components may be contained within the scope that does not hinder the effect of the present invention. From the perspective of raw material cost, the content of other components (the total amount when multiple components are included) is preferably 10% or less, and more preferably 5% or less in terms of mass percentage.

The glass used for the glass substrate 2 is not limited thereto, and for example, the glass composition may be a glass having, by mass%, SiO ₂ 58% to 70%, Al ₂ O ₃ 10% to 19%, B ₂ O ₃ 6.5% to 15%, MgO 0% to 2%, CaO 3% to 12%, BaO 0.1% to 5%, SrO 0% to 4%, BaO + SrO 0.1% to 6%, ZnO 0% to 5%, MgO + CaO + BaO + SrO + ZnO 5% to 15%, Li ₂ O + Na ₂ O + K ₂ O 0% to 0.5%, ZrO 5% to 20%, TiO ₂ 0% to 5%, and P ₂ O ₅ 0% to 5%; or a glass composition having, by mass%, SiO ₂ 55% to 70%, Al ₂ O ₃ Glass containing 10% to 20%, 0.1% to 4.5% B ₂ O ₃ , 0% to 1% MgO, 5% to 15% CaO, 0.5% to 5% SrO, 5% to 15% BaO, and 0% to 0.5% Li ₂ O + Na ₂ O + K ₂ O.

The thickness of the glass substrate 2 is not particularly limited. The thickness of the glass substrate 2 can be set to about 0.1 mm to 5 mm, for example.

The glass substrate 2 has a first main surface 2a and a second main surface 2b. The first main surface 2a and the second main surface 2b are opposite to each other. An anti-glare film 3 is provided on the first main surface 2a of the glass substrate 2.

The anti-glare film 3 has a concavo-convex structure. The anti-glare film 3 is provided to provide a so-called anti-glare effect, that is, to suppress the reflection of external light, etc. The anti-glare film 3 is a film having silicon oxide as a main component.

Furthermore, in this specification, the above-mentioned "main component" means that the film contains 50 mass % or more of the component, preferably 80 mass % or more of the component, and more preferably 90 mass % or more of the component. Of course, the film may also contain 100 mass % of the component.

The arithmetic mean height Sa of the surface 3a of the anti-glare film 3 is 0.3 μm or more. The arithmetic mean height Sa can be measured, for example, using an optical interference microscope or a laser microscope in accordance with ISO 25178. The arithmetic mean height Sa of the anti-glare film 3 can be increased by increasing the film thickness of the anti-glare film 3.

In addition, the pencil hardness of the anti-glare film 3 is 7H or more. The pencil hardness can be evaluated according to the principle, device, instrument, and procedure of the pencil hardness test in accordance with JIS K5600-5-4:1999. Specifically, a "uni" pencil (manufactured by Mitsubishi Pencil Co., Ltd.) can be used, the scratch distance can be set to 10 mm, and the surface 3a of the anti-glare film 3 can be observed with a metal microscope at a magnification of 100 times and epi-illumination to determine whether the surface 3a of the anti-glare film 3 has damage of more than 1 mm.

Since the coated glass substrate 1 of the present embodiment has the above-mentioned structure, it can achieve both anti-glare and scratch resistance to a high degree. Therefore, the coated glass substrate 1 of the present embodiment can be preferably used as a cover glass in a display of a mobile phone, a tablet terminal, a television, or a digital signage.

In the present embodiment, the arithmetic mean height Sa of the surface 3a of the anti-glare film 3 is 0.3 μm or more, preferably 0.32 μm or more, more preferably 0.33 μm or more, preferably 0.7 μm or less, more preferably 0.5 μm or less, and further preferably 0.45 μm or less. When the arithmetic mean height Sa of the surface 3a of the anti-glare film 3 is above the lower limit, the anti-glare property of the film-coated glass substrate 1 can be further improved. Moreover, when the arithmetic mean height Sa of the surface 3a of the anti-glare film 3 is below the upper limit, the anti-glare film 3 can be made less likely to be peeled off from the glass substrate 2.

In addition, the pencil hardness of the anti-glare film 3 is 7H or more, preferably 8H or more, and more preferably 9H or more. When the pencil hardness of the anti-glare film 3 is above the lower limit, the scratch resistance of the film-coated glass substrate 1 can be further improved. Furthermore, the upper limit of the pencil hardness of the anti-glare film 3 is not particularly limited, and can be set to 10H, for example.

Furthermore, the pencil hardness of the anti-glare film 3 can be measured according to the principle, device, apparatus, and step method described in JIS K5600-5-4:1999. The pencil hardness can be measured by scratching more than 10 times with a pencil of the same hardness, and the maximum hardness at which the damage rate is less than 30% is adopted. Furthermore, when preparing a plurality of film-coated glass substrates produced under the same conditions and evaluating the pencil hardness of each, if the pencil hardness obtained is different, the central value can be set as the pencil hardness.

In the present embodiment, the root mean square height Sq of the surface 3a of the anti-glare film 3 is preferably 0.30 μm or more, more preferably 0.35 μm or more, further preferably 0.40 μm or more, preferably 0.80 μm or less, more preferably 0.60 μm or less, further preferably 0.56 μm or less. When the root mean square height Sq of the surface 3a of the anti-glare film 3 is above the lower limit, the anti-glare property of the film-coated glass substrate 1 can be further improved. In addition, when the root mean square height Sq of the surface 3a of the anti-glare film 3 is below the upper limit, the anti-glare film 3 can be made less likely to be peeled off from the glass substrate 2.

The minimum self-correlation length Sal of the surface 3a of the anti-glare film 3 is preferably 1.5 μm or more, more preferably 3 μm or more, further preferably 5 μm or more, preferably 30 μm or less, more preferably 20 μm or less, further preferably 8 μm or less. When the minimum self-correlation length Sal of the surface 3a of the anti-glare film 3 is above the lower limit, the anti-glare property of the film-coated glass substrate 1 can be further improved. In addition, when the minimum self-correlation length Sal of the surface 3a of the anti-glare film 3 is below the upper limit, the glare called glare can be further suppressed.

Furthermore, the ratio (Sq/Sal) of the root mean square height Sq of the surface 3a of the anti-glare film 3 to the minimum autocorrelation length Sal is preferably 0.03 or more, more preferably 0.05 or more, further preferably 0.06 or more, preferably 0.10 or less, more preferably 0.08 or less, further preferably 0.07 or less. When the ratio (Sq/Sal) is above the lower limit, the anti-glare property of the film-coated glass substrate 1 can be further improved. Furthermore, when the ratio (Sq/Sal) is below the upper limit, the haze can be more reliably prevented from becoming too high.

The root mean square height Sq and the minimum autocorrelation length Sal can be measured, for example, in accordance with ISO 25178. Furthermore, the ratio (Sq/Sal) can be increased by increasing the film thickness of the anti-glare film 3 .

The average film thickness of the anti-glare film 3 is not particularly limited, and can be preferably designed to be 430 nm or more, more preferably 500 nm or more, further preferably 700 nm or more, preferably 2000 nm or less, more preferably 1500 nm or less, further preferably 1000 nm or less. Furthermore, the average film thickness of the anti-glare film 3 can be estimated based on the coating amount per unit area × liquid coating efficiency × solid content conversion concentration / film density.

In the present embodiment, the haze of the coated glass substrate 1 is preferably 30% or more, more preferably 40% or more, preferably 80% or less, and more preferably 60% or less. When the haze of the coated glass substrate 1 is above the lower limit, the anti-glare property of the coated glass substrate 1 can be further improved. Furthermore, when the haze of the coated glass substrate 1 is below the upper limit, when used in a display, etc., the visibility of the display surface can be further improved.

The haze of the film-coated glass substrate 1 can be measured, for example, in accordance with JIS K7136: 2000. In addition, the haze of the film-coated glass substrate 1 can be increased, for example, by increasing the film thickness of the anti-glare film 3 .

Hereinafter, an example of a method for manufacturing a film-coated glass substrate of the present invention will be described.

(Manufacturing method of film-coated glass substrate) In the manufacturing method of the film-coated glass substrate 1 of the present embodiment, first, a glass substrate 2 is prepared. As the glass substrate 2, the above-mentioned one can be used. In addition, the glass substrate 2 can be one having a functional layer on the surface of the substrate body. As the functional layer, there can be cited: a base coating layer, a close contact improvement layer, a protective layer, a coloring layer, etc.

Next, a coating liquid is applied on the prepared glass substrate 2 by spraying to form a coating film having projections and depressions.

The coating liquid contains a silica precursor. The silica precursor can be used as a matrix forming component when forming an anti-glare film by spray coating. By making the coating liquid contain a silica precursor, the adhesion with the glass substrate 2 can be improved and the refractive index can be consistent with the glass substrate 2.

As the precursor of silica, for example, a siloxane polymer can be cited. As the siloxane polymer, a silane oxide or a hydrolyzed condensate thereof is preferably used. Furthermore, the silane oxide preferably includes at least one of an N-functional silane oxide (N=2, 3, 4) and a hydrolyzed condensate thereof. As such a silane oxide, for example, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, etc., which are tetrafunctional silane oxides, can be cited.

In addition, the silane oxide may be a trifunctional silane oxide or a bifunctional silane oxide having an organic substituent such as an alkyl group, a vinyl group, a phenyl group, or an epoxide group. Examples of the silane oxide having an organic substituent include: methyltriethoxysilane, methyltrimethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane as trifunctional silane oxides; and dimethyldiethoxysilane, dimethyldimethoxysilane, etc. as bifunctional silane oxides. In the case of having such an organic substituent, the stress of the formed coating film can be reduced, and the occurrence of cracks can be further suppressed during the temperature rise process during sintering.

The silane oxides may be used alone or in combination of plural types.

The size of the siloxane polymer can grow by hydrolysis and condensation reaction. The size of the siloxane polymer can be set to 2 nm to 30 nm, for example, in terms of volume average.

The content of the silicon dioxide precursor is calculated as a mass percentage of silicon dioxide in the solid component, for example, 50% or more, preferably 60% or more, more preferably 70% or more, further preferably 80% or more, and particularly preferably 90% or more.

The coating liquid may contain an aluminum oxide precursor, a zirconium oxide precursor, a titanium oxide precursor, or a yttrium oxide precursor. These may be used alone or in combination. When the coating liquid contains an aluminum oxide precursor, a zirconium oxide precursor, a titanium oxide precursor, or a yttrium oxide precursor, the durability of the coating (coating film) may be further improved, and the matching of the refractive index of the coating (coating film) with the refractive index of the glass substrate 2 may be further improved.

The content of the aluminum oxide precursor, the zirconium oxide precursor, the titanium oxide precursor, or the yttrium oxide precursor (the total amount when multiple types are included) is calculated as the mass percentage of aluminum oxide, zirconium oxide, titanium oxide, or yttrium oxide in the solid component, and can be set to, for example, 0% to 30%.

Examples of the aluminum oxide precursor include aluminum alkoxides, hydrolyzed condensates of aluminum alkoxides, water-soluble aluminum salts, and aluminum chelates. Examples of the water-soluble aluminum salts include aluminum nitrate, aluminum chloride, aluminum sulfate, aluminum acetate, aluminum methylacetate, and aluminum acetate.

Examples of the zirconium oxide precursor include zirconium alkoxides and hydrolyzed condensates of zirconium alkoxides. Examples of the titanium oxide precursor include titanium alkoxides and hydrolyzed condensates of titanium alkoxides.

The coating liquid contains a solvent. The solvent is not particularly limited, and examples thereof include water, alcohols, ketones, ethers, solvents, esters, glycol ethers, etc. These solvents may be used alone or in combination.

Water can be used for the hydrolysis reaction of silane oxides, etc. However, if the water content is too high, the surface tension will be high, making the coating film prone to cracking. Therefore, the water content can be set to 3 to 6, for example, in terms of molar ratio relative to Si atoms.

In addition, from the viewpoint of making it easier to dry the coating liquid, the coating liquid preferably contains a solvent having a boiling point of less than 90°C. Examples of the solvent having a boiling point of less than 90°C include methanol, ethanol, isopropanol, tetrahydrofuran, hexane, etc. The content of the solvent having a boiling point of less than 90°C (the total amount when multiple solvents are included) can be set to, for example, 30% or more and 90% or less in terms of mass percentage of the entire coating liquid.

The coating solution may contain nanoparticles of metal oxide.

The content of the solid components in the coating liquid (heating residue) can be set to, for example, 1 mass % to 5 mass %.

When the coating liquid is applied, the coating liquid is sprayed onto the glass substrate 2 by a spraying method. Examples of the nozzle used for the spraying method include a dual-fluid nozzle, a single-fluid nozzle, etc., and preferably a dual-fluid spray gun using a dual-fluid nozzle. In this case, even if the coating liquid does not contain oxide particles, the unevenness of the anti-glare film 3 can be formed more efficiently. In addition, the adhesion between the glass substrate 2 and the anti-glare film 3 can be further improved.

The particle size of the droplets of the coating liquid ejected from the nozzle is usually 0.1 μm to 100 μm, preferably 1 μm to 50 μm. When the particle size of the droplets is above the above lower limit, it is possible to form a concave-convex surface that fully exerts the anti-glare effect in a shorter time. When the particle size of the droplets is below the above upper limit, it is easier to form a suitable concave-convex surface that fully exerts the anti-glare effect. Furthermore, the particle size of the droplets of the coating liquid can be appropriately adjusted according to the type of nozzle, air flow rate, spray volume, etc. For example, in a two-fluid nozzle, the higher the air flow rate, the smaller the droplets; and the greater the spray volume, the larger the droplets. Furthermore, the particle size of the droplets is the median diameter of the volume standard measured by a laser diffraction particle size distribution meter. The air flow rate can be set to 50 L/min to 300 L/min, for example. Moreover, the air pressure can be set to 0.1 MPa to 0.6 MPa, for example.

The spray gun distance can be set, for example, to be greater than 20 mm and less than 300 mm. The spray gun distance refers to the distance from the spray gun to the glass substrate 2 on which the film is to be formed.

The coating amount per unit area of the coating liquid can be set to, for example, 50 g/m ² or more, 80 g/m ² or more, 100 g/m ² or more, 200 g/m ² or less, 180 g/m ² or less, or 160 g/m ² or less. If the coating amount per unit area of the coating liquid is large, the arithmetic mean height Sa of the surface 3a of the anti-glare film 3 tends to increase, but it also varies depending on the solid content concentration of the coating liquid. In addition, there is a tendency for the film thickness of the anti-glare film 3 to increase. On the other hand, if the coating amount per unit area of the coating liquid is small, the arithmetic mean height Sa of the surface 3a of the anti-glare film 3 tends to decrease. In addition, there is a trend that the film thickness of the anti-glare film is decreasing.

The coating temperature of the coating liquid can be set to, for example, 10° C. or higher and 80° C. or lower.

The surface temperature of the glass substrate 2 when the coating liquid is applied is preferably, for example, 15° C. to 75° C. The humidity when the coating liquid is applied is, for example, 20% to 80%, and preferably 50% or more.

The drying temperature of the coating liquid is not particularly limited, and can be, for example, 25° C. or higher and 100° C. or higher, or 450° C. or lower and 400° C. or lower. The drying time can be, for example, 10 minutes or longer and 600 minutes or lower.

Next, the coated film is fired at a temperature of 500° C. or higher. Thus, the anti-glare film 3 is formed on the glass substrate 2, and the film-coated glass substrate 1 is obtained.

In the method for manufacturing the coated glass substrate 1 of the present embodiment, the anti-glare film 3 is formed by firing the coating film applied by spraying at a temperature above 500° C., so that the anti-glare property and scratch resistance of the obtained coated glass substrate 1 can be achieved to a high degree.

Previously, the anti-glare film thickness was increased to improve the anti-glare property, but the scratch resistance decreased. As a result, the anti-glare film was damaged a lot due to long-term use.

In contrast, the inventors have discovered that even when the thickness of the anti-glare film 3 is increased, the scratch resistance of the film-coated glass substrate 1 can still be improved by firing the coating film applied by spraying at a temperature above 500°C, thereby achieving both anti-glare and scratch resistance to a higher degree.

In the present embodiment, the calcining temperature of the coating film is 500°C or more, preferably 510°C or more, more preferably 520°C or more, further preferably 530°C or more, further preferably 540°C or more, particularly preferably 550°C or more, more particularly preferably 560°C or more, further particularly preferably 570°C or more, further particularly preferably 580°C or more, most preferably 590°C or more, particularly preferably 600°C or more, further particularly preferably 610°C or more, further particularly preferably 620°C or more, further particularly preferably 630°C or more, very preferably 640°C or more, further very preferably 650°C or more. In order to evaporate and burn the organic components (residual solvent, alkoxy, alkyl, vinyl, epoxy, etc. contained in the silicon dioxide precursor) remaining in the coating film and make the coating film dense, the higher the firing temperature, the better. The coating film after firing is preferably composed of only inorganic components. When the firing temperature of the coating film is above the above lower limit, the scratch resistance of the coated glass substrate 1 can be further improved.

On the other hand, the upper limit of the calcination temperature of the coating film is not particularly limited, and the calcination temperature is preferably below the strain point of the glass substrate 2. If the calcination temperature exceeds the strain point of the glass substrate 2, it will not be properly cooled and the glass substrate 2 will have residual strain, which is not good from the perspective of manufacturing cost. Therefore, from the perspective of further optimizing manufacturing cost or productivity, the firing temperature of the coating film is preferably below the strain point of the glass substrate 2, more preferably below (the strain point of the glass substrate 2 - 5°C), further preferably below (the strain point of the glass substrate 2 - 10°C), further preferably below (the strain point of the glass substrate 2 - 20°C), particularly preferably below (the strain point of the glass substrate 2 - 30°C), more particularly preferably below (the strain point of the glass substrate 2 - 40°C), further particularly preferably below (the strain point of the glass substrate 2 - 50°C), most preferably below (the strain point of the glass substrate 2 - 60°C), particularly preferably below (the strain point of the glass substrate 2 - 70°C), and even more particularly preferably below (the strain point of the glass substrate 2 - 80°C).

The baking time of the coating film is not particularly limited, but is preferably 10 minutes or longer, more preferably 30 minutes or longer, preferably 300 minutes or shorter, and more preferably 200 minutes or shorter.

The coating film is baked by, for example, a hot air heating device, a contact heating device, or a far infrared heating device.

[Second embodiment] FIG. 2 is a schematic cross-sectional view of a film-coated glass substrate of the second embodiment of the present invention. The film-coated glass substrate 21 is further provided with an anti-reflection film 24 on the anti-glare film 3.

The anti-reflection film 24 is preferably a dielectric multilayer film. In this case, when the coated glass substrate 21 is used in a display, etc., the image clarity can be further improved. In the present embodiment, the anti-reflection film 24 is a dielectric multilayer film formed by sequentially and alternately stacking a high refractive index film 25 with a relatively high refractive index and a low refractive index film 26 with a relatively low refractive index. Furthermore, the anti-reflection film 24 can also be a dielectric multilayer film formed by sequentially and alternately stacking a low refractive index film 26 with a relatively low refractive index and a high refractive index film 25 with a relatively high refractive index. Furthermore, the high refractive index film 25 and the low refractive index film 26 are preferably sputtered films. By setting such a structure, the adhesion between the high refractive index film 25 and the low refractive index film 26 can be improved.

Examples of the material of the high refractive index film 25 include niobium oxide, titanium oxide, zirconium oxide, niobium oxide, tantalum oxide, silicon nitride, aluminum oxide, and aluminum nitride.

Examples of the material of the low refractive index film 26 include silicon oxide, aluminum oxide, and magnesium fluoride.

The thickness of each layer constituting the antireflection film 24 is preferably greater than 1 nm and less than 500 nm, more preferably greater than 2 nm and less than 300 nm, and further preferably greater than 5 nm and less than 200 nm.

In the present embodiment, the total number of layers constituting the anti-reflection film 24 is 6 layers. However, in the present invention, the total number of layers constituting the anti-reflection film 24 is not particularly limited. The total number of layers constituting the anti-reflection film 24 is preferably 2 layers or more, and preferably 7 layers or less. By being within such a range, a film that can be effectively and easily formed can be produced.

The overall film thickness of the antireflection film 24 is preferably greater than or equal to 50 nm and less than or equal to 1000 nm, more preferably greater than or equal to 75 nm and less than or equal to 750 nm, and further preferably greater than or equal to 100 nm and less than or equal to 500 nm.

The anti-reflection film 24 can be formed, for example, by sputtering, CVD (chemical vapor deposition), or vacuum evaporation. In addition, the anti-reflection film 24 is preferably provided after the coating film is fired.

Other aspects are the same as the first implementation method.

In the coated glass substrate 21 of the present embodiment, the arithmetic mean height Sa of the surface 3a of the anti-glare film 3 is also greater than 0.3 μm, and the pencil hardness of the anti-glare film 3 is also greater than 7H. Therefore, in the coated glass substrate 21, both anti-glare property and scratch resistance can be achieved to a high degree.

Furthermore, in the first and second embodiments, the anti-glare film 3 is provided only on the first main surface 2a side of the glass substrate 2, but the anti-glare film 3 may be provided on both the first main surface 2a side and the second main surface 2b side of the glass substrate 2.

In the second embodiment, the anti-reflection film 24 is provided on the anti-glare film 3, but the anti-reflection film 24 may be provided between the glass substrate 2 and the anti-glare film 3. Furthermore, the anti-reflection film 24 may be provided on both the first main surface 2a side and the second main surface 2b side of the glass substrate 2.

Furthermore, a functional layer may be provided on either or both of the first main surface 2a and the second main surface 2b of the glass substrate 2 of the film-coated glass substrate 1 or 21. Examples of the functional layer include an antifouling layer, a protective layer, a coloring layer, a light shielding layer, and a decorative layer. Furthermore, the functional layers are preferably provided after the coating film is fired.

Furthermore, an anti-fouling layer may be provided on the outermost layer of the coated glass substrates 1 and 21 .

The present invention is described in detail below based on specific embodiments. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the gist.

Preparation of glass substrate A: Blend and melt glass raw materials so that the glass composition contains less than 0.1% alkali metal oxide by mass percentage, and use overflow down-draw method to form a plate to obtain a glass substrate A with a thickness of 0.5 mm. The strain point of the obtained glass substrate A is 685℃.

Preparation of glass substrate B: As glass substrate B, commercially available sodium calcium glass (strain point: 500°C) was prepared.

Preparation of coating liquid A: 0.4 parts by mass of water, 7.2 parts by mass of modified ethanol (containing 85.5% by mass of ethanol as the main component, and also containing methanol, etc.) and nitric acid were mixed with 1 part by mass of tetraethoxysilane (TEOS) and stirred to promote the hydrolysis and condensation reaction of TEOS, so that the size of the siloxane polymer grows, and the coating liquid A with a volume average size of 4.0 nm measured by dynamic light scattering measurement was obtained. Furthermore, the nitric acid was adjusted to a pH value of 4 and mixed. The concentration of the solid content (heating residue) converted to silicon dioxide in the obtained coating liquid A was 3.2% by mass. Furthermore, when measuring the scattered light intensity by the dynamic light scattering method, the product number "Zetasizer Nano S" manufactured by Malvern Panalytical was used.

Preparation of coating liquid B: After aging, 0.055 parts by mass of aluminum nitrate nonahydrate was added to coating liquid A, and the mixture was stirred to obtain coating liquid B. The total concentration of the solid components (heating residue) of the obtained coating liquid B in terms of silicon dioxide and alumina was 3.4% by mass. In addition, the ratio of silicon dioxide in the solid components was 95% by mass, and the ratio of alumina in the solid components was 5% by mass.

Preparation of coating liquid C: 0.4 parts by mass of water, 8.1 parts by mass of isopropyl alcohol, and nitric acid were mixed with 1 part by mass of tetraethoxysilane (TEOS) and stirred to promote the hydrolysis and condensation reaction of TEOS, so that the size of the siloxane polymer grew, and the coating liquid C with a volume average size of 3.9 nm measured by dynamic light scattering was obtained. Furthermore, the nitric acid was adjusted to a pH value of 4 and mixed. The concentration of the solid content (heating residue) of the obtained coating liquid C in terms of silicon dioxide was 2.9% by mass.

Preparation of coating liquid D: 0.064 mass parts of methyltriethoxysilane, 0.47 mass parts of water, 8.0 mass parts of modified ethanol (including 85.5 mass percent of ethanol as the main component and methanol, etc.), 0.93 mass parts of 1-butanol, and nitric acid were mixed with 1 mass part of tetraethoxysilane (TEOS) and stirred to promote the hydrolysis and condensation reaction of TEOS and methyltriethoxysilane, so that the size of the siloxane polymer grows, and the coating liquid D with a volume average size of 3.9 nm measured by dynamic light scattering measurement was obtained. In addition, the nitric acid was adjusted to a pH value of 4 and mixed. The obtained coating liquid D has a solid content (heating residue) concentration of 2.8% by mass in terms of silicon dioxide.

Preparation of coating liquid E: 0.095 mass parts of methyltriethoxysilane, 0.48 mass parts of water, 8.5 mass parts of modified ethanol (including 85.5 mass percent of ethanol as the main component, and also including methanol, etc.), 0.96 mass parts of 1-butanol, and nitric acid were mixed with 1 mass part of tetraethoxysilane (TEOS) and stirred to promote the hydrolysis and condensation reaction of TEOS and methyltriethoxysilane, so that the size of the siloxane polymer grows, and the coating liquid E with a volume average size of 3.9 nm measured by dynamic light scattering measurement was obtained. In addition, the nitric acid was adjusted to a pH value of 4 and mixed. The obtained coating liquid E has a solid content (heating residue) concentration of 2.8% by mass in terms of silicon dioxide.

(Example 1) A coating film was formed by spraying coating liquid A on glass substrate A. The coating amount during spraying was set to 116 g/m ² per unit area. A two-fluid spray gun was used, and the spray gun distance was set to 96 mm. The air pressure was set to 0.16 MPa, and the liquid spray amount was set to 0.2 kg/hour.

Next, the obtained coated glass substrate was placed in a hot air heating furnace, and the temperature was raised from room temperature to 600°C in 1 hour, and then maintained at 600°C for 30 minutes. Thereafter, the temperature was lowered to room temperature in 2 hours. Thus, a coated glass substrate with an anti-glare film formed on the glass substrate was obtained.

(Examples 2 to 9 and Comparative Examples 1 to 5) The types of glass substrate and coating liquid, spraying conditions (coating amount, air pressure, spray gun distance), and firing temperature were changed as shown in Table 1 below. Otherwise, the same operation as in Example 1 was performed to obtain a film-coated glass substrate.

[Evaluation] (Evaluation of gloss, haze, and glitter) For the coated glass substrates obtained in Examples 1 to 9 and Comparative Examples 1 to 5, gloss, which is an indicator of gloss, haze, which is an indicator of whiteness, and glitter, which is an indicator of glare, were measured. Gloss was measured based on JIS Z 8741:1997 using Micro gloss (60°) (manufactured by BYK) to measure the gloss of the coated glass substrate at an incident angle of 60°. Haze was measured based on JIS K 7136:2000 using NDH-5000 (manufactured by Nippon Denshoku Co., Ltd.). Flash was measured using SMS-1000 (manufactured by Display Messtechnik & Systeme) in the flash measurement mode.

(Evaluation of reflection) For the coated glass substrates obtained in Examples 1 to 9 and Comparative Examples 1 to 5, the angle distribution of the reflected brightness of the line light source was measured in the reflection measurement mode of SMS-1000 (manufactured by Display Messtechnik & Systeme). Based on the measured distribution, the regular reflection brightness Rs and the reflection brightness R(1) and R(-1) with a deviation of 0.1° and -0.1° from the regular reflection angle were read, and the ratio of Rs/[arithmetic mean of R(1) and R(-1)] was calculated and used as the reflection value. The smaller the value, the less reflection and the higher the anti-glare performance. In addition, the above measurement was performed using a lens with a focal length of 16 mm at an operating distance of 410 mm.

(Evaluation of pencil hardness) The pencil hardness of the coated glass substrates obtained in Examples 1 to 9 and Comparative Examples 1 to 5 was evaluated. Specifically, under the load and speed of the pencil hardness test described in JIS K5600-5-4:1999, a pencil with a hardness of 7H (manufactured by Mitsubishi Pencil Co., Ltd., "uni") was used to draw a line at a distance of 10 mm, and then the pencil powder was wiped off. Whether damage was caused was determined by observing the indentation at a magnification of 100 times under the epi-illumination of a metal microscope to confirm whether damage of more than 1 mm was caused. Repeat the scratches 10 times, and evaluate the damage rate to be 30% or less as ○, and evaluate the damage rate to be greater than 30% as ×. In addition, the same test was performed with pencils of other hardness, and the maximum hardness at which the damage rate was less than 30% was set as the pencil hardness. In addition, for the pencil, each scratch was performed using sandpaper according to the steps described in JIS K5600-5-4:1999, and used for evaluation.

(Evaluation of surface roughness) For the coated glass substrates obtained in Examples 1 to 9 and Comparative Examples 1 to 5, the surface roughness was evaluated according to ISO 25178.

Specifically, an optical interference microscope (manufactured by Ryoka Systems, "VertScan R5300", version: VS-Measure Version 5.05.0001, CCD (charge coupled device) camera: SONY HR-571/2, objective lens: 20X, barrel: 1XBody, wavelength filter: 530 white, measurement mode: Wave, field size: 316.77 μm×237.72 μm, resolution: 640×480) was used to measure the height distribution of the surface. Furthermore, based on the measured height distribution, the analysis software VS-Viewer Version 5.05.0001 was used to interpolate the Bad Pixels and perform a surface correction to calculate the arithmetic mean height Sa, the root mean square height Sq, and the minimum autocorrelation length Sal (the distance at which the autocorrelation function decays to 0.2). Furthermore, in order to facilitate the measurement, a 100 nm thick aluminum film was formed on the sample surface before the measurement. The film was formed by sputtering.

The results are shown in Tables 1 and 2 below.

[Table 1] Coating liquid Glass base board Coating amount (g/m ³ ) Air pressure(MPa) Spray gun distance (mm) Firing temperature(℃) Embodiment 1 Liquid A Substrate A 116 0.16 96 600 Embodiment 2 Liquid A Substrate A 154 0.20 96 600 Embodiment 3 Liquid B Substrate A 154 0.24 96 600 Embodiment 4 Liquid C Substrate A 116 0.16 96 600 Embodiment 5 Liquid A Substrate A 116 0.16 96 560 Embodiment 6 Liquid A Substrate A 154 0.16 96 560 Embodiment 7 Liquid A Substrate B 116 0.16 96 560 Embodiment 8 Liquid D Substrate A 142 0.16 96 650 Embodiment 9 Liquid E Substrate A 185 0.16 96 650 Comparison Example 1 Liquid A Substrate A 93 0.16 96 350 Comparison Example 2 Liquid A Substrate A 116 0.16 96 350 Comparison Example 3 Liquid A Substrate A 154 0.20 96 350 Comparison Example 4 Liquid C Substrate A 116 0.16 96 350 Comparison Example 5 Liquid D Substrate A 142 0.16 96 350

[Table 2] Gloss(%) Fog(%) Flash(%) Reflection Pencil hardness 7H Pencil hardness JIS K5600-5-4:1999 Arithmetic mean height Sa(um) RMS height Sq(um) Minimum autocorrelation length Sal(um) Sq/Sal Embodiment 1 26 33.0 4.2 1.51 ○ 9H 0.331 0.415 7.3 0.0569 Embodiment 2 20 45.1 3.1 1.46 ○ 9H 0.337 0.424 5.7 0.0748 Embodiment 3 twenty one 44.3 3.0 1.35 ○ 9H 0.344 0.412 5.6 0.0730 Embodiment 4 26 32.2 4.3 1.32 ○ 9H 0.301 0.371 7.2 0.0515 Embodiment 5 26 34.0 4.0 1.46 ○ 9H 0.337 0.442 7.2 0.0612 Embodiment 6 twenty one 42.5 3.6 1.15 ○ 9H 0.428 0.552 7.9 0.0703 Embodiment 7 26 33.5 4.0 1.46 ○ 9H 0.330 0.440 7.2 0.0611 Embodiment 8 twenty one 40.3 3.1 1.15 ○ 9H 0.306 0.360 5.1 0.0705 Embodiment 9 20 47.2 3.0 1.21 ○ 9H 0.406 0.469 5.6 0.0836 Comparison Example 1 33 25.5 4.5 2.08 ○ 7H 0.268 0.349 6.9 0.0503 Comparison Example 2 twenty three 35.1 4.0 1.39 × Less than 7 hours 0.360 0.456 7.2 0.0632 Comparison Example 3 17 48.5 2.9 1.35 × Less than 7 hours 0.354 0.439 5.7 0.0768 Comparison Example 4 twenty three 36.0 3.7 1.31 × Less than 7 hours 0.335 0.416 6.8 0.0616 Comparison Example 5 18 47.1 2.6 1.08 × Less than 7 hours 0.369 0.430 5.1 0.0843

(Evaluation of image distortion) The surface opposite to the surface on which the anti-glare film is formed is illuminated by a fluorescent lamp or other linear light, and the image is observed. In Examples 1 to 6, 8, 9, and Comparative Examples 1 to 5, image distortion was not observed on the entire surface of the film-coated glass substrate, and in Example 7, image distortion was observed in a portion of the film-coated glass substrate. In Examples 1 to 6, 8, 9, and Comparative Examples 1 to 5, the strain point of substrate A was higher than the firing temperature, so it is believed that the residual strain is less.

(Evaluation of cracks) The surface of the anti-glare film was observed at a magnification of 100 times under the epi-illumination of a metal microscope. The results showed that cracks were partially observed in Examples 2, 3, and 6. On the other hand, in Examples 1, 4, 5, and 7, which had a smaller coating amount than these, or in Comparative Examples 1 to 5, which had a lower firing temperature than these, and in Examples 8 and 9, which used methyltriethoxysilane, the generation of cracks was suppressed. In particular, in Examples 8 and 9, although the coating amount was larger and the firing temperature was higher, the generation of cracks was still suppressed, which can be said to have taken into account both reflection and hardness to a higher degree.

1: Glass substrate with film 2: Glass substrate 2a: 1st main surface 2b: 2nd main surface 3: Anti-glare film 3a: Surface 21: Glass substrate with film 24: Anti-reflection film 25: High refractive index film 26: Low refractive index film

FIG. 1 is a schematic cross-sectional view showing a glass substrate with a film in the first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a glass substrate with a film in the second embodiment of the present invention.

Claims (8)

A film-coated glass substrate, comprising: a glass substrate; and an anti-glare film, which is disposed on the main surface of the glass substrate and has silicon oxide as the main component; and the arithmetic mean height Sa of the surface of the anti-glare film is greater than 0.3 μm, and in the pencil hardness test of JIS K5600-5-4:1999, when the surface of the anti-glare film is observed at a magnification of 100 times using a metal microscope to determine whether the surface of the anti-glare film is damaged, the pencil hardness is greater than 7H. The coated glass substrate of claim 1, wherein the haze measured in accordance with JIS K7136:2000 is greater than 30%. The coated glass substrate of claim 1 or 2, wherein the strain point of the glass substrate is above 550°C. For example, in the coated glass substrate of claim 1 or 2, the ratio of the root mean square height Sq of the surface of the anti-glare film to the minimum autocorrelation length Sal (Sq/Sal) is greater than 0.05. A method for manufacturing a film-coated glass substrate, comprising: Forming a coating film having a concave-convex surface by spraying a coating liquid containing a silicon dioxide precursor on a glass substrate; and Forming an anti-glare film by firing the coating film at a temperature above 500°C; and Forming the anti-glare film in such a way that the arithmetic mean height Sa of the surface of the anti-glare film becomes 0.3 μm or more. A method for manufacturing a coated glass substrate as claimed in claim 5, wherein when the coated film is fired, the coated film is fired at a temperature below the strain point of the glass substrate. A method for manufacturing a coated glass substrate as claimed in claim 5 or 6, wherein the strain point of the glass substrate is above 550°C. The method for manufacturing a coated glass substrate as claimed in claim 5 or 6, wherein the silicon dioxide precursor comprises: at least one of an N-functional silane oxide (N=2, 3, 4) and a hydrolysis condensate of the N-functional silane oxide.